Date: 3/30/21 12:04 am
From: Robert O'Brien <baro...>
Subject: [obol] Nailing Scaup Identification
As Lars has said, although both are diving ducks, Lesser Scaup seem to
prefer smaller or at least shallower water while Greater Scaup are the
These are an interesting pair, identification wise. (Behaviorally as well,
I would guess, but I don't know anything about that).
As found in any field guide:
Lesser Scaup are somewhat smaller with somewhat smaller, narrower bills & a
smaller nostril, a purplish head reflection, a more peaked head profile,
sometimes with an apparent indentation on the sides of the head, and a
shorter wing stripe.
Greater Scaup the opposite in all respects, a greenish head reflection, and
a somewhat wider bill and fatter, rounded head.
The head reflection is quite dependent upon the angle and brightness of the
sun and can simnply look all dark in poor lighting.
And then there is the 'tip', which allows nailing the identification.
Greater Scaup has a much more pronounced, wider nail as Roy has described
in detail.
A compromise between the deepwater Columbia and shallower inland ponds is
perhaps found at Vanport Wetlands, the ponds *west* of the Expo Center,
that is
At least these waters (largely unvegetated) are close to the Columbia..
This is a good place for direct comparison on a lucky day.
The two attached photos were taken there in late winter last year
As you can see by the camera's numbering, the photos were taken a minute or
two apart in good light.
Their bills are pretty similar, but the Lesser's being somewhat more
slender; the head peaking is apparent in Lesser. Head
reflections correspond to above.
But.....................I'm having a hard time *nailing* this
I am NO scaup expert, I just took their photos. But the nails on this
pair would likely be the last thing I would rely on.
Looking forward to comments from Roy and all others.
Bob OBrien Carver OR

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